2012 FRC Team 1717 Uncut

[jakemochas]

Originally Posted by msimon785

I know from our mentors that they utilize their gyro to make the controls driver-relative and thus location-aware. In other words, regardless of the orientation of the robot, if the driver moves the joystick forward, the robot will travel away from him. This was done to make it more intuitive to the driver. With that said, I only know this of their 2011 (non-independent) swerve system, and even then you will need a 1717 student to confirm and expand on that.

Last year and in all previous years, we did not utilize a gyro with our swerve drivetrain. As a result, all previous robots have been driven from a robot-centric view.

Originally Posted by JamesTerm

All of this is absolutely amazing... I gotta ask... would you mind sharing how the controls are mapped to the drive. In particular the spin and pivot. (We like to call this slide turning). Was it intuitive to the driver and useful to have and use?

Because the drivetrain was capable of such complex maneuvers, a goal for the programming team this year was to make the robot as easy to drive as possible. This was incredibly important because we are all seniors and our team has rookie drivers every year. Almost everyone on our team has been capable of driving the robot in a rudimentary fashion when using the joysticks for the first time. They really enjoy the simplicity and the intuitive nature of the controls.

This year, the simplicity of the driver’s controls were particularly important. Our drivers had never driven a FIRST robot because we were moving into our new facility. As a result, we were not able to give them the proper introduction to driving a robot. The first time our drivers were able to drive a robot was 2 weeks after build season ended when we finished our practice robot. Before the LA Regional, our drivers had less than 10 hours of driving practice.

The layout for the driver’s controls and programming implementation are as follows:

The driver has 2 joysticks to control the drivetrain. Like last year, the left is used to translate the robot in any direction and the right joystick’s x-axis is used for rotating the robot. Unlike last year, however, this year we used a gyro to make the controls for the drive field-centric. If our driver pushes the joystick away from himself, the robot moves away from him regardless of the robot’s orientation.

The gyro makes basic driving easier, but it also makes it possible to spin while driving. All the driver does to spin while driving, or “slide turn”, is move the left and right joysticks together. The robot moves with the direction and speed of the left joystick. The robot’s spin speed and spin direction are dictated by the right joystick. Spinning while driving has become an integral part of all of our driver’s maneuvers. The spinning while driving made it much easier to avoid defensive robots, collect balls, lineup for shots, and make final adjustments on the bridge.

To pivot around a specific wheel, we used 4 buttons that each correspond to one of the wheel modules on the robot. When the driver holds down one of those buttons, the right joystick’s spin commands adjust to pivot around that wheel. The pivots about a single wheel were used less frequently, but helped in situations where we wanted to maneuver around a robot that was pushing us or line up at the fender after collecting a ball from in front of the fender.

Spinning while driving became natural for our drivers because of its implementation and joystick mapping. Our robot was able to perform maneuvers in the game that were not possible in previous years. An example of our robot’s maneuverability can be seen in the slalom swerve video from our original post.